Cutter for lawn-mowers.



' 3. CASE. OUT 03 LAWN MOWERS. APPLICATION FILED SEPT. 22, 1908.

. 924,318. Patented June 8, 1909;

- WITNESSES: l/VKENTOR.

A TTORNEY.

{ certain pronounced advantages over the conpushing out must result fromany blade arrmrr s rn enrich.

CUTTER FOR LAWN-IVIOWERS.

Specification of Letters Patent.

Patented June 8, 1909.

Application filed September 22, 1908. Serial No. 454,148.

To all whom it may concern:

Be it known that I, ADELBERT B. CASE, a citizen of the United States ofAmerica, residing at Springfield, in the county of Hampden and State ofMassachusetts, have invented new and useful Improvements in Cutters forLawn-Mowers, of which the following is a specification.

This invention relates to lawn mowers and is in the nature of animprovement on the construction described and claimed in my LettersPatent for improvement in rotary 18, 1906 under No. 838,521. In saidpatent the cutting blade is described and claimed as consisting of ablade whose cutting edge is bent back relatively to the direction ofrotation thereof so as to form a surface that stands at an angle to thebody portion of the blade, said bent surface being substantially at aright angle to the fixed blade of the mower. The particular form ofblade described and claimed in my said prior patent, and its relation tothe fixed blade, possesses struction generally in use at the time saidpatent was issued, which generallyaccepted type is illustrated inFigurel of my said pate ent. A comparison of the construction claimed insaid patent (together with that which forms the subject matter of thepresent application) with the generally accepted construction of thecutting elements as typified in Fig. 4 of said patent will show that thesubject matter of this application is in the nature of a further advancealong the same path as indicated in said patent, viz.,in the perfectionof a construction whereby a drawing out of the rotating blade across theedge of the stationary blade may be attained as compared with thepushing out which is a feature characteristic of lawn mowerconstructions prior to the invention covered in my said patent, it beingobvious that the rangement in which the angle of the adjacent rotatingand fixed blade surfaces is greater than a right angle at the point oftheir operative contact.

Referring to the present invention, the drawings forming part of thisapplication have been made with a view of clearly disclosing the step inadvance of the patented construction above referred to, Fig. 1 being asectional elevation of the stationary blade and part of the rotatingblade of a lawn mower embodying the construction forming the subjectmatter of my prior patent herein referred to. Fig. 2 being a like viewof similar parts constructed according to and embodying in its preferredform the subject matter of the present invention.

Referring to these drawings: In each of the figures thereof, aindicatesthe shaft carrying the rotary blades of a lawn mower only one of which,I), is shown, this being mounted in the usual manner in any desirableway on the shaft, as for example, by means of the spiders c to which theblades are riveted.

The stationary blade is indicated by d, this being riveted in the usualmanner to a web or bar e extending transversely between the two sideframes of the machine.

It will be noted, by referring to Fig. 1, that the grass to be cut(indicated herein by f) is in a substantially perpendicular position atthe moment of cutting, whereas, by referring to Fig. 2, it will beobserved that the form of the rotating blade 1), near the cutting edgethereof, is such that the shoulder g is formed thereon on the forwardside of the blade in proximity to the cutting edge thereof, thisshoulder extending from one end of the blade to the other, whichshoulder is forward of, or projects beyond the cutting edge h of theblade. The object of so forming the blade is to bend the free ends ofthe grass backward over the edge of the fixed blade prior to theengagement of the cutting edges of the rotary and the fixed blades. Theeffect of this is tl1reefold,first, it makes a break in the stalk of thegrass over the sharp edge of the stationary blade which, as is wellknown, makes it possible to more easily sever the same second, by sobending backward the ends of the tufts of grass over the edge of thestationary blade prior to the severing thereof, said tufts serve to holdthe machine to the ground whereby the jumping of the same on relativelyuneven ground is prevented to a very great degree; and, third, itprovides a cutting edge for the revolving blade so located relative tothe body of the blade that it is drawn across the edge of the stationaryblade instead of being pushed across said edge: and the fact that thefree ends of the grass are bent backwardly and downwardly over thecutting edge of the stationary blade by the movement of the shoulder 9over the edge of the stationary blade in advance of the engagement ofthe cutting edges of the blades and the cutting edge of the rotary bladeis then drawn over the edge of said stationary blade, greatly reducesthe power necessary to rotate the shaft a to elect the cutting of thegrass. Furthermore, the holding of the machine to the ground in themanner described produces a much more even surface of cut lawn than ispossible when the machine is free to jump more or less when operated ona lawn having an uneven or rough surface.

A further material advantage inherent in the construction describedherein is the fact that the cutting edge of the blade I) need not besharp to do good work though the edge of the stationary blade at shouldbe. Furthermore, by reason of the peculiar cross sectional form of theblade I) it any hard substance be interposed between the movable andstationary blades in operating the machine the cutting edge of the bladeI) will not come in contact therewith but such object will be struck bythe shoulder g on said blade and jammed against the edge of thestationary blade and very little damage to the machine would result forthe reason that the stationary blade in lawn mower constructions is madevery hard.

The blade 6 may be made in any manner which will result in the provisionof a rib or shoulder having the function of the shoulder 9 describedherein, that is to say the specific cross sectional l'orm illustratedand described in this application might be varied with greater or lessextent but any form of blade whereby the grass may be bent backward overthe edge of the stationary blade prior to being cut, is deemed to be theequivalent of the form of blade shown herein and to embody the essentialelements 01' this invention.

In the drawings, the arrow m indicates the direction of rotation of therotating blade 1),

and the arrow 0 the direction ol' movement of the machine in cutting thegrass, and where the word forward has been used in the siecification. todesignate one side of the blade I) that side is meant which is firstpresented to the stationary blade.

hat I claim, is:

1. A lawn-mower comprising a stationary blade and a movable blade, saidmovable blade having a shoulder thereon near its eutting edge wherebythe grass may be bent over the edge of the stationary blade in advanceof the meeting of the cutting edges of the two blades.

2. In a machine for cutting grass, two blades,one being movable relativeto the other,one of said blades having means to bend the grass down overthe edge ol the other blade prior to the severing ol the grass.

3. A lawn mower comprising a rotating blade and a stationary blade, saidrotating blade having a shoulder extending from end to end thereofparallel with, and near, its eutting edge, and so positioned as to passover the edge of the stationary blade in advance of the cutting edge ofthe rotating blade to bend the grass backward over the stationary bladeprior to cutting it.

4. A lawn mower having a movable blade and a stationary blade, saidmovable blade having its cutting edge so positioned that at the meetingof the cutting edges of said two blades an acute angle will be formedbetween the innnediately contiguous surfaces of said two blades at thetrout ol' the movable blade, whereby a drawing out of the edge of themovable blade over the edge of the stationary blade may be effected.

ADE LBEH 'l B. (EASE. lVitnesses WM. H. CHAPIN, K. I. CLnMoNs.

